9,612 research outputs found
Composing Control Barrier Functions for Complex Safety Specifications
The increasing complexity of control systems necessitates control laws that
guarantee safety w.r.t. complex combinations of constraints. In this letter, we
propose a framework to describe compositional safety specifications with
control barrier functions (CBFs). The specifications are formulated as Boolean
compositions of state constraints, and we propose an algorithmic way to create
a single continuously differentiable CBF that captures these constraints and
enables safety-critical control. We describe the properties of the proposed
CBF, and we demonstrate its efficacy by numerical simulations.Comment: Submitted to the IEEE Control System Letters (L-CSS) and the 2024
American Control Conference (ACC). 6 pages, 3 figure
Predicting Muscularity-Related Behavior, Emotions, and Cognitions in Men: The Role of Psychological Need Thwarting, Drive for Muscularity, and Mesomorphic Internalization
We examine the relationships that internalization, need thwarting (NT), and drive for muscularity (DFM), along with their interactions, had with weightlifting, muscle dissatisfaction (MD), and muscle-related-worry (MRW). A sample of 552 men (MAGE = 20.5 years, SD = 3.1) completed the Psychological Need Thwarting Scale, the Internalization subscale of the male version of the Sociocultural Attitudes Towards Appearance Questionnaire, the Drive for Muscularity Scale-Attitudes subscale, the Male Body Attitudes Scale-Muscularity subscale, the Body Change Inventory-Worry subscale, and an inventory assessing weightlifting behavior. DFM significantly predicted weightlifting, MRW, and MD. Internalization significantly predicted weightlifting and MRW. NT significantly predicted weightlifting and MD, and its relationship with MRW approached significance. The interaction terms did not predict weightlifting or MRW. The NT/DFM and NT/Internalization interaction terms predicted MD. These results highlight the role of NT in predicting appearance variables in men
On the Safety of Connected Cruise Control: Analysis and Synthesis with Control Barrier Functions
Connected automated vehicles have shown great potential to improve the
efficiency of transportation systems in terms of passenger comfort, fuel
economy, stability of driving behavior and mitigation of traffic congestions.
Yet, to deploy these vehicles and leverage their benefits, the underlying
algorithms must ensure their safe operation. In this paper, we address the
safety of connected cruise control strategies for longitudinal car following
using control barrier function (CBF) theory. In particular, we consider various
safety measures such as minimum distance, time headway and time to conflict,
and provide a formal analysis of these measures through the lens of CBFs.
Additionally, motivated by how stability charts facilitate stable controller
design, we derive safety charts for existing connected cruise controllers to
identify safe choices of controller parameters. Finally, we combine the
analysis of safety measures and the corresponding stability charts to
synthesize safety-critical connected cruise controllers using CBFs. We verify
our theoretical results by numerical simulations.Comment: Accepted to the 62nd IEEE Conference on Decision and Control. 6
pages, 5 figure
Numerical Studies of QGP Instabilities and Implications
Because the initial shape of the QGP in a heavy ion collision is anisotropic,
the momentum distribution becomes anisotropic after a short time. This leads to
plasma instabilities, which may help explain how the plasma isotropizes. We
explain the physics of instabilities and give the latest results of numerical
simulations into their evolution. Nonabelian interactions cut off the size to
which the soft unstable fields grow, and energy in the soft fields subsequently
cascades towards more ultraviolet scales. We present first results for the
power spectrum of this cascade.Comment: Talk given at workshop on Quark-Gluon Plasma Thermalization, Vienna,
10-12 August 2005. 8 page
How should discrepancy be assessed in perfectionism research? A psychometric analysis and proposed refinement of the Almost Perfect Scale–Revised
Research on perfectionism with the Almost Perfect Scale-Revised (APS-R) distinguishes
adaptive perfectionists versus maladaptive perfectionists based primarily on their responses to
the 12-item unidimensional APS-R discrepancy subscale, which assesses the sense of falling
short of standards. People described as adaptive perfectionists have high standards but low levels
of discrepancy (i.e., relatively close to attaining these standards). Maladaptive perfectionists have
perfectionistic high standards and high levels of discrepancy. In the current work, we re-examine
the psychometric properties of the APS-R discrepancy subscale and illustrate that this
supposedly unidimensional discrepancy measure may actually consists of more than one factor.
Psychometric analyses of data from student and community samples distinguished a pure fiveitem
discrepancy factor and a second four-item factor measuring dissatisfaction. The five-item
factor is recommended as a brief measure of discrepancy from perfection and the four-item
factor is recommended as a measure of dissatisfaction with being imperfect. Overall, our results
confirm past suggestions that most people with maladaptive perfectionism are characterized
jointly by chronic dissatisfaction as well as a sense of being discrepant due to having fallen short
of expectations. These findings are discussed in terms of their implications for the assessment of
perfectionism, as well as the implications for research and practice
R&D results on a CsI-TTGEM based photodetector
The very high momentum particle identification detector proposed for the
ALICE upgrade is a focusing RICH using a C4F10 gaseous radiator. For the
detection of Cherenkov photons, one of the options currently under
investigation is to use a CsI coated Triple-Thick-GEM (CsI-TTGEM) with metallic
or resistive electrodes. We will present results from the laboratory studies as
well as preliminary results of beam tests of a RICH detector prototype
consisting of a CaF2 radiator coupled to a 10x10 cm2 CsI-TTGEM equipped with a
pad readout and GASSIPLEX-based front-end electronics. With such a prototype
the detection of Cherenkov photons simultaneously with minimum ionizing
particles has been achieved for the first time in a stable operation mode
Electronic Transport in the Oxygen Deficient Ferromagnetic Semiconducting TiO
TiO films were deposited on (100) Lanthanum aluminates
LaAlO substrates at a very low oxygen chamber pressure
mtorr employing a pulsed laser ablation deposition technique. In previous work,
it was established that the oxygen deficiency in these films induced
ferromagnetism. In this work it is demonstrated that this same oxygen
deficiency also gives rise to semiconductor titanium ion impurity donor energy
levels. Transport resistivity measurements in thin films of TiO
are presented as a function of temperature and magnetic field. Magneto- and
Hall- resistivity is explained in terms of electronic excitations from the
titanium ion donor levels into the conduction band.Comment: RevTeX4, Four pages, Four Figures in ^.eps forma
The effect of geometry on charge confinement in three dimensions
We show that, in contrast to the flat case, the Maxwell theory is not
confining in the background of the three dimensional BTZ black-hole (covering
space). We also study the effect of the curvature on screening behavior of
Maxwell-Chern-Simons model in this space-time.Comment: 8 pages. To be published in Europhysics Letter
- …